The statements in this section merely provide background information related to the present disclosure and do not constitute prior art.
In monitoring an object by using an image surveillance, changes in color of pixels are detected, and the pixels exhibiting changes in color are observed for a certain time and determined to be the pixels of an object which is stolen or left unattended, depending on gradient information.
However, color changes due to full or partial illumination (shading, turning on lights, and turning off lights) frequently occur in images monitored in real-time. The inventor(s) has noted that color-based image detection is likely to lead to an incorrect determination due to sensitive response to changes in illumination. The inventor(s) has noted that in addition to such issues as color changes by illumination, the detection speed is lowered since the determination of an object left unattended and theft are performed independent of extraction of candidate objects. Moreover, the inventor(s) has experienced that to utilize gradient information in determining such events as leaving an object unattended and theft, a calculation time is needed for extracting the gradient information as well as 3-dimensional color information, thereby making it difficult to implement real-time processing.